Calculating instrument



April 15, 1941. H. w. KUBLER CALCULATING INSTUMENT Filed May 2, 1939 Patented Apr. 15, 1941 UNITED STATES PATENT OFFICE 2,238,529 CALCULATING INSTRUMENT Hans Wolfgang Kiibler, Berlin, Germany Application May 2, 1939, SerialNo. 271,380 11 Claims. (01'. 235-70) The need tor a simple and handy calculating instrument with which the four kinds oi calculation, namely multiplication, division, addition and subtraction can be carried out is very great. The size of the instrument should be such that it can be carried in the pocket. For calculating adding machine, which is made of metal, has on the guides of the slide of the slide-rule which must necessarily be elastic, having regard to the fact that the adding machine must be fitted to the back of the logarithmic slide-rule in order to satisfy the requirement that the complete instrumentshould be handy and of pocket size.

The body of the slide-rule and also the slide are usually made of a material which imdergoes considerable alterations under the effect of heat and atmospheric moisture, namely materials such as Celluloid, artificial resin, wood and so forth. Slide-rules usually have a resilient base-plate by which the guides-in which the tongues of the slide run are pressed gently against the tongues. This is necessary in order that, if contraction or xpansion of the material of which the slide-rule "is made occurs, the slide may still be moved regularly and uniformly.

It now the adding machine which is made of metal is attached rigidly to this resilient baseplate, the important resiliency of the base-plate of the slide-rule would be completely eliminated, the consequence oi which would be that the slide could not be moved evenly in its guides.

In order now to provide a combined instrument which is of pocket size and as handy as possible and in which the slide can be moved evenly along the slide-rule and, at the same time, not to endanger the strength 01' the connection between the slide-rule and the adding machine, according to the present invention the adding and subtraeting machine is fixed to the middle part of the back or; a logarithmic slide-rule having a resilient base, in such a manner that the side edges of the slide-rule can bend freely in both directions about the points at which the sliderule is fixed to the adding machine.

The metallic adding machine is preferably provided with a separate additional rear wall which has no direct connection with the interior mechanism of the adding machine and isrigidly connected only to its casing. The adding machine can then be fixed to this additional wall in such a manner that the places of attachment are located only in the central longitudinal part of the slide-rule.

In order that the invention may be readily understood and carried into efiect'several forms of construction of a calculating instrument in accordance with the invention are illustrated by way of example in the accompanying drawing, in which Figure 1 is a' perspective-view of one form of the instrument, one half of the slide-rule being cut away.

Figure 2 is a section on the line 2-2 oi Fig. 1. Figure 3 is a perspective view of a second form of construction in which a part of the slide rule is also cut away.

Figure 4 is a cross-section on the line 4-4 of Fig. 3.

Figure 5 is a perspective view of a third form of construction in which a part of the slide-rule is again cut away, and

Figure 6 is a view showing the front of the adding machine part of the instrument.

Referring to the drawing, the general construction of the logarithmic slide-rule is well known. It consists of a resilient'base-plate 8, two lateral guides 2 and 3 and a slide l. The guides ,2 and 3 are rigidly attached to the resilient base-plate i. made of Celluloid.

The flat adding and subtracting machine is also well known as regards its general construction. It is, for example, of the kind described in the U. S. Patent specification No. 1,596,108. The adding and subtracting machine is provided with a casing 5 having slots 6 for adding and slots I for subtracting. Below these slots there are numeral slides 8 which can be shifted by means of a pointed instrument 9. The numeral slides 8 are supported and guided on a back wall Id.

In the form of construction illustratedin Figs. 1 and 2 an additional back wall II is arranged over the back wall ll! of the adding machine.

This back Wallis fixed only to the casing 5 of the adding machine; it has no direct connection with the interior of the adding machine.

The back wall H extends over the entire length and width of the adding machine. To the back wall ii there are riveted three plates ll of which The base-plate i is usually in Figure l the plate at one end is wholly visible while only half of the second centre plate can be seen in this figure. The third plate is located on the other end of the back wall I I in a similar position to the first plate I2. Th rivets I! by which the plates are fixed to the wall I I are situated in the longitudinal centre line of the wall I I. The plates are so shaped that their ends I4 will easily bend at right angles to the surface of the wall II. The plates are preferably made of a material which can easily be stuck on, for example of Celluloid, artificial resin, glazed cardboard and the like.

The resilient base-plate I is stuck to the resilient ends I4 of the plates I2. The resiliency of the plates I2 can be increased by reducing their cross-section in the vicinity of the central axis w-c of the additional wall II, for example by means of recessed or cut out portions I5.

By sticking the resilient base-plate I of the slide-rule to the ends II of the plates I2 in this way the additional advantage is obtained that the resilient base-plate I of the slide-rule can b kept very thin in the middle. when any adhesion is effected with a Celluloid or Bakelite or similar solution, which is necessary for the purpose, it is found that expansion occurs at the place of adhesion if the materials are too thin.

This expansion which is of course harmful, cannot occur when the adherence is effected in the manner described since the adhesion takes place only at the thickest parts of the slide-rule namely at the placewhere the guides 2 are situated.

As may be seen from Figure 2 when the instrument is assembled there are gaps l8 at the side.

edges between the slide-rule and the adding machine. Since now the two parts of the instrument are connect-ed together only along the centre line a-a, side edges of the slide-rule can bend freely towards both directions, that is to means of rivets II, which pass through the spring base I of the slide-rule. The rivets I! are again situated in the centre line H of the instrument. The intermediate space between the slide-rule and the adding machine which is necessary for enabling the side edges of the slide-rule to bend. is obtained by means of small washers I8 which are interposed between the base I and the separate wall I I. This form of construction is suitable for an instrument in which the base I of the slide-rule has sufiicient strength or thickness.

In the form of construction according to Figs. 5 and 6 a narrow strip I9 of Celluloid, artificial resin, glazed cardboard or the like is used for flxing;the slide-rule to the separate additionalwall II of the adding machine. This strip is again situated in the centre line H of the instrument. The strip I8 is fixed by means of rivets 20 to the separate wall of the adding machine. The base I of the slide-rule is stuck to the strip I9. This form of construction is also preferably employed when the base I is not excessively thin in the middle.

I claim:

1. A mounting means for'attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calcuinherent flexibility of said slide rule about its longitudinal axis comprising means secured to said rigid wall of said casing and means connecting said first mentioned means and said resilient base so as to space said resilient base from said casing to permit flexing of said resilient base about its longitudinal axis.

2. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calculating mechanism and the like so as to retain the 'inherent flexibility of said slide rule about its longitudinal axis comprising an auxiliary wall secured to said rigid wall and flexible means connecting said auxiliary wall and said resilient base.

3. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calculating mechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an auxiliary wall secured to said rigidwall and means whereby said auxiliary wall is attached to the back of said resilient base in such a manner that the side edges of the slide rule are able to bend transversely to the longitudinal axis of said rule.

4. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calculating mechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an additionalback fixed to said rigid wall of said casing and plates which are fixed to said additional back at points along its longitudinal center line and are attached to the back of said resilient base at points outside lating mechanism and the like so as to retain the said center line,'- so that the plates are able to bend transversely with respect to said center line.

5. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calculating mechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an additional back flxed to said rigid wall of said casing. and plates which are fixed to said additional back at points along its longitudinal center line and are attached to the back of said resilient base at points outside said center line. so that the plates are able to bend transversely with respect to said center line. and the width of said plates being decreased transversely of said center line from the outside towards the center.

6. A mounting means for attaching aslide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a cal culatingmechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an additional back fixed to said rigid wall of said casing and plates which are fixed to said additional back at points along itslongitudinal center line and are attached to the back of said resilient base at points outside said center line, so that the plates are able to bend transversely with respect to said center line, and rivets securing said plates to'said additional back.

7. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a plates which are riveted to said additional back at points along its longitudinal center line and of which the width decreases from the outside towards the center, said plate being attached to the back of said resilient base at points away from said center line.

8. A mounting means'for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calculating mechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an additional back fixed to said rigid wall of said casin plates which are riveted to said additional back at points along its longitudinal center line and of which the width decreases from the outside towards the center, said plates being attached to the back of said resilient base at points away from said center line by adhesive and the central portions of said plates being free from said resillent base.

. 9. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing. of a calculating mechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an additional back fixed to said rigid wall of said casing, rivets disposed in the longitudinal center line' of said resilient base, whereby said additional back is fixed to said resilient baseand washers around said rivets whereby said additional back is spaced away from said resilient base.

10. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calculating mechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an additional back fixed to said rigid wall-of said casing, a strip attached to said additional back along its longitudinal center line and means whereby said strip is attached to the back of saidresilient base.

11. A mounting means for attaching a slide rule or similar construction having a resilient base to a substantially rigid wall of the casing of a calculating mechanism and the like so as to retain the inherent flexibility of said slide rule about its longitudinal axis comprising an additional back fixed to said rigid wall of said casing, a strip attached to said additional back along its longitudinal center line and means whereby said strip is attached to the back of said resil-= ient base, and said strip being riveted to said additional bac 7HANS WOLFGANG KiiBLER. 

